Exploring Cellulose in the design and synthesis of covalent adaptable networks: a route towards recyclable and sustainable thermosets

Thermosets are known for their poor (re-)processing and recycling capabilities due to theirpermanently crosslinked microstructure. As a result, their end-of-life options are limited to landfill orincineration, preventing thermosetting materials from meeting the demand for sustainable andcircular materials. In recent years, the introduction of dynamic covalent bonds in polymeric networkshas formed a promising solution to the challenge of developing circurlar thermosets. So-calledcovalent adaptable networks (CANs) bear reversible bonds that can form or break upon a stimulus(i.e. heat, mechanical stress, UV-radiation etc.), thus producing materials with inherent recycling andreprocessing capabilities. While research initially mainly focused on the preparation of CANs fromfinite petroleum-based resources, conflicting with fully circular design, the focus now turned to theuse of alternative and renewable resources. In this regard, applying cellulose as a resource for thesynthesis of renewable CANs is an attractive alternative. Cellulose is the most abundant naturalpolymer and is associated with multiple advantages including low cost, renewability, biodegradabilityand great mechanical performance. Chemical modification of cellulose presents a challenge, but stillthe large number of hydroxy groups makes cellulose potentially suitable for a wide range of chemicalmodifications. This projects explores the design and synthesis of cellulose-based CANs, focussing on the modification and crosslinking of cellulose with different dynamic chemistries.